Hello, first time growing and transplanting a cactus. I purchased 4, I removed all from their old pots, let’s roots dry out for 24hrs, removed old dirt from roots, then put them in bonsai jack cactus mix. All seem to be doing well but this guy has started to show discoloration. I have not watered any of them since the replant 2 weeks ago. All are in direct sunlight in my window for 6-7hrs a day. Is this normal for my cactus?